Pat Perez produced an impressive second round to take a two-shot lead at the top of the leaderboard in the Wells Fargo Championship at Quail Hollow in Charlotte.
Having scored a five-under 67 on day one, Perez continued to pick up the shots on Friday with nine birdies and two bogeys taking his total to 12-under.
Overnight leader Bill Haas has Perez in his sights, though, and lies tied for second place with Jonathan Byrd.
Local boy Haas, who learned his trade on the Charlotte course, dropped his first shot of the tournament on the 17th, but birdies on the fifth, 14th and 15th holes allowed him to move on to 10 under.
"I just basically wanted to try to hit it like I hit it yesterday and give myself chances, which I felt like I did today pretty well," Haas said afterwards on www.pgatour.com.
"Driving the ball is key on this course. If you get it in the fairway then you can hit the greens."
Byrd also built on his first-round score of six under by adding six birdies in his second round. However, his card could have looked even better but for a double bogey on the par-four 14th.
Phil Mickelson made the biggest leap up the board with six birdies in a blemish-free round taking him to nine under and within touching distance of the top three.
Lucas Glover also sits on nine under, but had a mixed day on the course with seven birdies and three bogeys.
Vijay Singh, Carl Petterson and Stewart Cink are a shot further back, while England's Brian Davis lies five shots off the leader alongside Webb Simpson and Steve Marino.
Davis began the day on two under and dropped just one shot to complete the second round in five-under 67.
Defending champion Rory McIlroy saw his tournament come to a premature end, however, missing the cut on three over following a level-par second round.
Paul Casey was another casualty, paying the price for a terrible opening day.
The Englishman resumed on six-over, and although there was a marked improvement with five birdies and one bogey, the damage had already been done.